Reinforcer efficacy in a delayed matching-to-sample task.
Five domestic hens were exposed to a delayed matching-to-sample task. Conditions 1, 5, and 8 were variable-delay conditions in which five delays (0.25, 1, 2, 4, and 8 s) from the red or green sample to the presentation of the red and green comparison stimuli were presented a number of times during each session. In the fixed-delay condition (Condition 3), each delay was presented for 15 sessions under a Latin square design across birds. When improvements in accuracy across the variable-delay conditions are taken into account, the data were similar under both the variable and fixed delays. In Conditions 2, 4, 6, and 7 sample-reinforcer intervals were held at 8, 8, 4, and 2 s, respectively, while sample-choice intervals were varied within these during each session. With increasing sample-reinforcer interval, both initial discriminability (i.e., with sample-choice delay = 0) and rate of decrement in discriminability decreased. Although the former would be predicted if accuracy depends of the average sample-reinforcer interval, the latter would not. These data show that increasing the sample-choice interval had less effect on matching accuracy than increasing the sample-reinforcer interval did.
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Department of Psychology, University of Waikato, Hamilton, New Zealand.
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D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002645:Chickens / Q000502:physiology; D002755:Choice Behavior / Q000502:physiology*; D008568:Memory / Q000502:physiology; D012054:Reinforcement, Psychology; D013997:Time Factors